Two-cycle gasoline engine



July 4, 1950 B. M. IKERT 2,513,563

TWO-CYCLE GASOLINE ENGINE Filed July 5, 1947 3 Sheets-Sheet 1 2 1 IN V EN TOR.

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TWO-CYCLE GASOLINE ENGINE Filed July 5, 1947 5 SheetsSheet 2 IN VEN TOR.

@ yezz/ July 4, 1950 Filed July 5, 1947 B. M. IKERT TWO-CYCLE GASOLINE ENGINE 3 Sheets-Sheet 3 2 j 1 w INVENTOR.

firzzzzom f/ ferf A Q Q Patented July 4, 1950 UNITED STATES OFFICE Application July 5, 1947, Serial No. 759,014

4 Claims. 1 This invention pertains to new and useful improvements vin-two cycle gasoline engines.

The chief and general object of this invention is toprovide -a two cycle engine of increased efflciencyanol of simple, low'cost construction.

Another purpose of the invention is the provision in a two-cycle gasoline engine of structural improvements urin the crank case for increasing the explosive power of the gasoline mixture by enhancing the volatility'thereof in that means :are provided in-said crank: case for heating the fuel and causing its entrance. into the firing chamber under pressure anda high degree of turbulence;

Yet another object-ofthe invention' is to provide a two cycle enginehavi-ng a pistonythe outer top surface of which isso shaped as to take full advantage of the explosion of the gas,- to more effectively inhibit mixture" of unexplodedfuel and the exhaust gases,- and to. permit exhaust gases-and to permit exhaust-of the burned gases immediately once full advantage has been taken of 'thB fOI'CG of their explosion.

How the above objectsand advantages and: still others'incident. to the invention are accomplished is setforth-in'the' detailed description which follows and shown on the somewhatrdiagrammatic drawings in which Fig; 1 is acrosssectiona1 sideviewof a typi- I cal engine lookingwin' the: direction-at which the crankshaft extends transversely of the engine a structure; I

Fig-:2 is a cross-sectional'view taken'substantially along-the-line 22 of Fig.1;-

Fig. 3 isa cross-sectional plan'view-takensubstantially'along the line 3'3of Fig: -2;'and

Fig. 4 is a cross-sectional plan View taken sub'-,

stantially along the line 4+4 of- Fig. v2.

In terms ofbroad, general inclusion the twoconveying, fuel turbulent, shoulder'portions as-' sociated with thecrankcase which extend a distance" into the path of the piston: and adjacent towhich .the fuel vaporizing means may: discharge into the crankcase, a fuel conveying passageway between" the crankcase and thezcylindery and-a novel zpiston'," the head-t ot: which'integrallyc:can:

ries 'a baffle so constructed as to guide the incoming unexploded fuel upwardly. and to guide-the exploded fuel downwardly inthe retracted position of-the pistons Referring nowto the drawings,.reference nu-.

meral I0 indicates. the base or support for the comprises a fuel tank-ll havingafiller opening closed by screw. cap lB the former. being held by appropriate supports I9..: Afuel line .20 having in its length. ashut-off Ivalve 2| isin communication' betweenw tank 17 and a conventional carburetor 22.- The outlet throat 23 .ofcarburetor ZZcOmmunicates-With.an attaching flange 24 bolted to cylinder block [2 and this flange communicates withfuel inlet port more fully. described hereinafter.

At one side of the-engine is a hood or-housing 25. which isadapted .to act as a guiding scoop for-heatdissipating. airblast past the fins [3, I5 'provided bya crankshaft-attached..fan or combined flywheeland .fanwhich is enclosed in I this housing. The :hereinbefore. described fanor flywheel-and fancis conventional hence is not shown onthe drawings.

crankcase-I I, in a single cylinder engine such as vherein. shown, is comprised of. two generally sim'ilarw opposed castings 3i], 3! having integral opposed matching semicircular. verticalconnecting flanges 32, 33, saidcastings held-in proper relative positions. by machine screws. 3%, which extend through these flanges.v The upper portionsrof castings 3!, .32 are provided with outward-1y extending horizontal flangesfidldt, respectively, which abut the lower surfaces of a corresponding flange 31-. onthelower end :of cylinder block -I 2, being attached theretobymachine screws 38.

Interiorly, each crankcase-forming casting 39,

512iis hollowed out in a series of concentric an-- nular steps to provide space for the rotation of a the crankshaft crank 39 and its integral-counterbalances 4|,"4i-andto' accommodate 'a "pair" Extending upwardly Closing the outer end of cylinder block l2 3 of spaced crank shaft supporting roller bearings 42, 42. As best seen in Fig. 1, castings 30, 3| are each also bored for tight fitted outward passage therethrough of the extremities of crankshaft 45. Crank 39 has conventionally mounted on it one end of a connecting rod 46, the other end of the latter being conventionally-mounted on wrist pin 41 mounted on piston Rearwardly of wrist pin 4'! piston 50 has 2. depending hollowed out skirt 5| the lower annular extremity of which, in most retracted position of the piston, travels about to the open lower end of cylinder block l2.

Still referring to Fig. 1, each crankcase forming casting 30, 3| has formed integral with it a solid shoulder 52 which, as shown in Fig. 4, is of generally semi-cylindrical form and, as shown in Fig. 1, is of such length and so 'positioned as to extend a substantial distance into depending piston skirt 5| in the most retracted position of piston 50.

In the assembled condition of the engine, shoulders 52, 52 are laterally spaced a distance from the inner cylinder block wall 53 to admit piston skirt 5| between their semi-cylindrical outer surfaces and cylinder wall 53, a small space 54 being left between the outer shoulder surfaces and the interior surface of skirt 5|. Also, as shown in Fig. 4, a transversely extending opening 55 is provided between shoulders 52, 52 for passage therebetween of connecting rod 40, and each shoulder preferably has its upper end arcuately dished out as at 56 to permit close positioning of the shoulders to the piston wrist pin carrying trunnions 51, 51.

As best shown in Fig. 2, the wall of cylinder block l2 has an opening 58 therein in communication with carburetor throat 24 and this opening is positioned immediately above the upper peripheries of shoulders 52, 52 so that the volatilized fuel discharged by the carburetor 22 will be discharged thereby in close contact with the shoulders. The position of opening 58 with respect to piston 50 is such that in most extended position of such piston the opening is in open communication with the space above shoulders 52, 52 to admit the fuel'mixture into crankcase M.

As will be obvious from Figs. 1 and 2, the integral relationship. of shoulders 52, 52 with the assembled crankcase H and the connected relation of the crankcase with cylinder block l2, coupled with the close proximity thereto of piston 50, permits such shoulders to become quite heated by transference of heat from such closely associated parts during engine operation.

As shown in Fig. 2, preferably in diametrically opposed relationto opening 58 is a fuel passageway 59 between crankcase H and cylinder block l2. This passageway is unrestricted at its juncturewith the crankcase, but at its upper and cylinder connecting end is divided into a pair of spaced fuel inlet ports 60, Bll. Preferably opposite to inlet ports 60, 60 are a plurality of exhaust outlet ports each indicated by reference numeral 6| which extend through the wall of cylinder block l2 and communicate with an exhaust outlet pipe 62. v

i As best shown in Fig. 2, it will be noted that the upper portions of outlet openings indicated by reference numerals 6| are arranged in a higher horizontal plane than the upper portions of fuel inlet openings 60, 6D for reasons to be brought out later herein;

As shown in Figs. 2 and 3, the upper surface of piston 50 is in part horizontally planar as at fit tends in this relation transversely of the piston head at its other end to have at its one side the fuel inlet ports 60, 60 and the exhaust outlet ports 6|, 6|.

Generally medially of bafiie H is a horizontally planar portion 12 of circular plan view appearance which is in vertical register with the firing points of spark plug I6. Extending outwardly from planar baflle position 12 transversely of the engine fuel inlet and exhaust outlet ports are opposed wings I3, 13. Baffle H and wings l3, 13 present to the fuel inlet ports an abruptly vertical and medially horizontally outwardly curved surface. indicated by reference numeral M. Opposite vertically abrupt surface M, baffle H is formed into a downwardly inclined semi-circular surface 15 which merges with the planar piston head surface HI immediately in front of the exhaust outlet ports.

Two cycle engines, when in operation, at certain times invariably have in their crankcases a partially vacuous condition which permits their crankcases to form part of the fuel intake system. In the case of the instant invention it will be apparent that during the upstroke of piston 50 the piston will pass and wholly close off cylinder fuel inlet ports 60, 60 and the exhaust ports indicated by reference numerals M. This piston upstroke will generally cause the gaseous content of the crankcase to be reduced to less than outside atmospheric pressure so that when piston skirt 5| passes fuel intake port 58 a charge of carburetor-vaporized or atomized fuel will be drawn into crankcase As previously stated, the incoming charge enters the crankcase immediately above shoulders 52, 52. Since the shoulders extend substantially into piston skirt 5|, downstroke of piston 50 will force the vaporized charge against the shoulders 52, 52 and in resisting compression the vapor will seek an outlet which it will find in the openings 54 and 55 arranged between and around such shoulders.

The downward stroke of piston 59 also tends somewhat to compress the fuel vapor and since inlet port 58 will then be closed by the piston wall the gasified fuel in seeking an outlet will pass up fuel passageway 50 to pass, when the piston is sufiiciently retracted into the cylinder through ports 60, 60'. The vertically abrupt face of 14 of bafile U will cause the fuel to be directed vertically and particularly in and around the firing points of spark plug I6.

On the upstroke of piston 40 the fuel charge is compressed whereupon, in proper usual relation to the downstroke of the piston the sparkproviding electrical system (conventional, and not shown) causes the sparkplug to jump a firing spark across its terminals, exploding the fuel.

It will be obvious that the maximum force of the explosion is directed against planar bafiie surface 72. The piston is thus precipitately forced downward until the upper end of exhaust ports 6| are exposed, whereupon the high velocity exploded gas follows the downwardly sloping contour of bafile surface 15 being substantially disposed of before the upper portion of fuel inlets 50 are exposed by the retracting piston and a new piston and connecting rod in their close proximity to shoulders 52, 52 will exert tremendous turbulence to the carburetor-vaporized fuel discharged adjacent the shoulders. It will also be obvious that once the engine has been a while in operation heat transfer from the cylinder walls will take place causing the shoulders to become quite hot and the restricted areas of passage for the vaporized fuel will cause the fuel to absorb a quantity of this desirable heat. Thus it may be accurately said that a highly desirable fuel turbulence and heat absorption takes place with corresponding increase in fuel volume and explosiveness.

It is characteristic of two cycle engines that at one position of the piston (see Fig. 1) both inlet and exhaust ports are simultaneously open and this necessary condition is one of the factors making the achievement of high efficiency in such engines a very considerable problem.

The form of piston head baflie H is a far step in the direction of increased efiiciency in that the vertically abrupt but medially outwardly curved face 14 thereof causes the incoming fuel mixture to be principally directed away from the outgoing exhaust gases and in the direction of cylinder head M. The horizontal planar top surface i2, being located vertically directly below the terminals of the sparkplug [6 received the brunt of the exploded charge and more efiiciently passes on this energy for translation into rotary motion in the crankshaft. The downwardly slanted baifle area 75 permits more efiicient self propelled disposal of the exhaust gases.

While the invention has been shown and described with considerable particularity it is realized that modifications thereof may be made, hence it is desired that the detailed disclosure be taken as illustrative rather than in a limiting sense.

I claim:

1. In a two-cycle engine having a cylinder, a crankshaft and a connecting rod carried thereby, a crankcase having therein a space for rotation of said crankshaft and connecting rod, said crankcase comprising two similar portions fixed in opposed relation to one another, each portion having on it a heat-exchange shoulder extending into said cylinder.

2. In a two-cycle engine, the combination of a connected cylinder block and crankcase, a piston, connecting rod and crankshaft interconnected with one another within said cylinder block and crankcase, a shoulder portion within said crankcase, said shoulder portion extending substantially into the rearwardmost portion of said piston in the retracted position thereof, carburetor means discharging into said crankcase adjacent said shoulder portion, fuel conduit means between said crankcase and the interior of said cylinder block forwardly of said piston, said piston having a fore-end baffle comprising a planar area and at each side thereof outwardly directed wings, and laterally of said wings, an abrupt surface on one side and a downwardly sloped surface on the other side.

3. In a two-cycle gas engine, a piston having a head comprising two generally annular planar surfaces generally parallel to one another at different elevations, said upper planar surface being disposed generally medially of said lower planar surface and of less area than the latter, opposed aligned wings extending outwardly from each side of said upper planar surface and connected with said lower planar surface and extending across the latter at one side of a line denoting its diameter, said wings joining said lower planar surface at substantially right angles at one side and at the side opposite that of its right angled relation to said lower planar surface said wings merging with an angularly downwardly directed surface of generally semi-annular configuration in plan view which extends downwardly from said upper planar surface and merges with said lower planar surface adjacent the edge thereof.

4. In a two-cycle engine the combination comprising a block having a piston-receiving cylinder formed therein and a crankcase, an integrated piston, connecting rod and crankshaft operative within said cylinder and said crankcase, said crankcase comprising two similar portions fixed in opposed relation to one another and each of said crankcase portions having a shoulder thereon, said shoulders extending into the rearward part of said piston in the retracted position thereof, carburetor means discharging into said crankcase adjacent said shoulders and at one side of said block, said block having a fuel passageway formed therein at a side opposite the discharge port of said carburetor means and communicating between the interior of said crankcase and said cylinder forwardly of said piston, the fuel discharged by said carburetor means passing around said crankshaft in its path of travel and being thrown into extreme turbulence by the movement of said crankshaft. 

